1. Field of the Invention
This invention directs itself to a method of preparing a Pap smear. In particular, this invention directs itself to a method for combining cytological samples from multiple sites into a single specimen. More in particular, this invention directs itself to a brush overlay method wherein the application of the final cytological sample is combined with samples which have been previously obtained and applied to a slide, wherein the sample contained within the interstices of the cytological brush are simultaneously combined with the other samples and distributed uniformly across the surface of the slide. Further, the means for combining and distributing the multiple samples utilizes a light downward pressure, normal to the surface of the slide, while simultaneously rotatively displacing the cytological brush in a single direction, or alternately the brush is reciprocated back and forth across the surface of the slide.
2. Prior Art
Devices for collecting cytological samples, and methods of preparing Pap smears are well known in the art. The best prior art known to the Applicant include U.S. Pat. Nos. 3,640,268; 3,881,464; 4,127,113; 4,227,537; 4,620,548; 4,754,764; 4,759,376; 4,762,133; 4,873,992; and, 4,936,312.
Some prior art systems, such as that shown in U.S. Pat. No. 4,754,764 are directed to cervical cytology devices for simultaneously sampling both the exocervical and endocervical areas. However, the device is formed as a two-part structure, such that subsequent to sampling the two parts are separated, and the cells collected by each portion are disposed on separate slides. Thus, while the collection of the cytological samples is made more efficient, the laboratory must still examine two separate specimens. The two slides must be separately screened and evaluated by the pathologist, thereby essentially doubling the cost to the patient.
In other prior art systems, such as that disclosed in U.S. Pat. Nos. 4,127,113; 4,227,537; and 4,759,376 cytological brush systems are disclosed. While such prior art systems disclose the transfer of the cytological sample obtained with the brush by rotating the brush and streaking it longitudinally across the surface of the slide, such is for the distribution of a single sample. Therefore, each of these systems is intended to obtain an endocervical sample for application to a slide, but they do not disclose or suggest the method of the instant invention.
Other prior art systems, such as disclosed in U.S. Pat. No. 4,620,548 are directed to devices for collecting cytological samples from multiple sites. While such systems disclose the combination of two samples, one obtained by aspiration, and the other by means of a scraper, the samples are combined and distributed by a smearing action. In such systems, the aspirated sample is pooled onto a slide followed by the rubbing of the scraped sample therewith. The combined sample is then spread across the surface of the slide by the longitudinal displacement of a cylindrical surface portion of the instrument. However, such mixing and distribution of the sample does not provide the necessary uniformity for accurate microscopic evaluation, as achieved by the method of the instant invention. The uniformity of the sample is critically important to the accuracy of the laboratory evaluation. If an unsatisfactory slide results, then the sample taking procedure must be repeated. Further, this prior art technique does not disclose or suggest a method by which more than two samples can be combined to provide a single slide specimen.